Begin with your hands and knees on the floor, with your hands underneath your shoulders and your knees under your hips. Keeping the right knee bent 90 degrees, lift the left leg until it is parallel to the floor.
Keep the left thigh still as you straighten your left knee, kicking your leg out to the side. Don't let the leg lower as you kick.
Bend the left knee back to 90 degrees, and then lower the leg to the floor. Do this exercise with your right leg to complete one rep.